Safety-coupling.



R. T. 'rlAZELTOl\Il SAFETY COUPLING.

APPLICATION msn 1AH.5,1915.

atented June l, 1915 nonnen r. .Haznnron or crnonrlv'eri,

HIO, ASSIGNOR TO THE CINCINNATI MLLNG -MACHINE CMNY, OF CINCXNNATI, OHIO, A COBEORATION Ol? OHIO.'

SAFETY-consiliare.

inslaan 'To all 'wiz om 'it may concern Be itlinown that l, ROBERT T. HAzrL'roN,

a citizen of the United States, and residing isv at Cincinnati, in the county of Hamilton and State of Ghio,'have invented a new and Improved Safety-Coupling, of which the following specification is a full disclosure.

This invention relates 'to -a mechanism whereby only such stresses and strains as fall belou a pre-determined maximum may be transmitted, whereby the transmission elements may not Suder injury in case an ultimately movedA part should encounter and los impeded by an abnormal resistance.

@ne object Within the contemplation of this invention is to create a transmission arrangement which embodies the advantages of a positive drive, as of the so-called shearpin type, as Well as the advantages of an impositiva y drive, as of the friction-drive type; While at the same time eliminating certain disadvantages of each tino?. systems.

4Another object is to provide a safety device capable of transmitting positively and Without slipping any load less thansa predetermined maximum and which will be certain to yield or fail to transmit stresses exceeding said maximum Within aceurately deiined limits.

.A more concrete object is to render available aA power-transmitting mechanism which will adord a positive drive and which will not creep like an imperfect friction-drive and yet which will safely yield in case of undue stress and at once restore itself to its normal transmitting conditions to insure a positive drive and avoid the loss of time of a shear-pin arrangement, which requires the replacementof the sheared element after it has functioned. Y Another object is to create an' organization as above stated in which the pressures will be Well balanced and confined only to the operatlin surfaces thereby avoiding the necessityfo building, maintaining and lubricatingspecialthrust-bearings. w

Another object is to formulate an arrangement in which the stresses are ybalanced throughout and in which the construction is sosimplc and elementary-that it may be manufactured at a stalled lWith facility in various 'types of machines.

'Specification of Letters Patent.

of said disminimum cost and Patented I une i,

app'nwuon and January 5,1915. serian no. ses.

Another object is to materially improve f the combination more fully described and claimed in the patent of Hazelton @t Einstein, No. 1,125,686 issued January 19th, 1915, by avoiding the use of shear-pins, while yet insuring a positive transmission free from creeping as to the feeding of-the table and also rendering certain a yield atthe desired strain, While yet permitting a momentary discontinuance of the transmission in case of undue table resistance.

Other objects will be in part obvious from the annexed drawings and in part indicated in connection therewith by 'the following analysis of this invention.

This invention accordingly consists in the features of construction, combination olu Earts and in the unique relations of the memers and in. the relatife proportioning and disposition thereof; all as more completely outlined, herein.

To enable others skilled in the art so fully to comprehend the underlying features thereof that they may embody the same by the numerous modifications in structure an:1

Continuing now by way of a more detailed l description, it may be stated that the illustrated embodiment of this invention contem-` plates two series of hardened steel halls mutually combined with a Y{list-member inter- I vening 4between each of. thetvvo series of balls and with a coperating member in part disposed on the outer side of the one series of balls and in part disposed 'on the outer or more remote side of the other series of balls; all in coperati ve relation with resilient means whereby each series of balls will impede a relative rotary movement otsaid members and Will so carry the pressures as substantially to balance the two members against relative movement in lateral or axial direction. i

Referring to the drawings, A indicates what may he termed the intervening transmission-member and B, B1 and B2 'indicate the parts constituting the circumscribing or non-intervening transmission-member. Motion is caused to fiow from the one member to the other through the instrumentality of a peculiar transmitting means embodying two series of hardened balls.

The intervening transmission member A here assi-mes the form of an annular sleeve having a hub 3 an aperture 1 whereby it may be fitted to a power transmitting shaft or the like and may be connected thereto against relative movement as by means of the keyavay 2 and a suitable cooperating key. This intervening member is provide with a series of apertures 4: which are in this embodiment extended in a direction parallel with that of the surface whereby the member is secured to the power-shaft or the like. That is to say, these apertures are preferably arranged in form of an equi-spaced circumerential series, each aperture extending parallel with the axis of the member and at such a distance therefrom as to provide a sufficient moment arm. These apertures 4 are adapted snugly to retain the balls of at least one of the corresponding series of hardened steel balls and the ball-receiving apertures are suliciently deep so that under certain conditions said balls may retreat or be forced more -or less completely into said apertures, although normally about a hemisphere only o each ball will be contained Within the aperture or socket. Preferably, however, the apertures 4: are open at each end and extend from one side to the other of the member and the diameter of these apertures is preferably slightly greater than that ot the balls, soas to permit one series of balls, as represented by C, to be stationed at one end of the apertures ll; andin like manner to enable the other series of balls D to be stationed at the other side of the member A. This arrangement is convenient inasmuch as it enables a single expansile spring 5 to serve for each `pair of balls by thrusting them in'oppositc directions away from the intermediate plane of the member A. By this construction, no strains tending to shift it are imposed on the member A by the springs 5, and regardless ot the strength of the springs. -there is no tendency to shift the position of the member A laterally, 'L'. e., in an axial direction, and consequently the member A docs not have to be held in position by means of special thrustbearings which are always liable to give trouble.

The companion member B is constructed und arranged to receive the pressures of the series of balls C and l) in such a Way that the said pressures are always balanced. This is accomplished by forming the meme ber B with a shoulder or annular side-Wall 6 which muy conveniently be formed integrally with the member B.- The complementary element or part B2, as a matter of convenience in assembling and in enabling the pressures to be adjusted, is separably secured to the member B. Thus, the part B2 here assumes the form of a collar adapted to be telescoped by the overhanging annular portion 7 of ,the member B, and it is pref' vented from rotating therein by means of a. key d. This collar is adjustable in an axial direction by means of a cap or adjuster B1.

Now, inasmuch as the shoulder or side-wall 6 and the collar B2 are each'provided with a series oi ball-seatsl10 spaced 1n registry with the apertures 4, it Will springs movement between the members A and can be permitted only in casethe turning balls C 'and f f D toward one another against the resistance p moment is sufficient to force the of the 'springs 5.

lt has been found by practical tests that this arrangement is not only Well balanced,

in that it avoids the necessity for tlaruat bearings, but to all intents and pur oses 1t is a positively acting mechanism 1n t at motion is transmitted Without permittingf) of any slipping or creeping. t has also een demonstrated by practical tests that this mechanism may be depended upon to yield at about the same stress or load. A great difficulty with ordinary friction devices and with shear-pin couplings is that it is always doubtful as to just what load will be eiective to produce a yield', and it has been found in practice that such devices are very unreliable and in some instances will unexpectedly transmit dangerous loads. closed construction, however, will be found always to yield withiny narrow 'limits at the load determined by each specific adjustment,

Way expected.

A material advantage of this construction over the ordinary balleratchets, which embody a single series of balls, lies in the fact that it is quite devoid of unbalanced forces and therefore its utility and adaptability in connection with machine tools is greatly enhanced. y

The drawings illustrate one of the many possible combinations that may be made of this mechanism with the driving and driven elements ot a machine tool. Thus, in this instance, the part E receives the power. or motion in the first instance from a suitable prime mover of the machine tool. 'and it is connected with one or the other of the members A and B to propel the same. I This part E is here shown as a power shaft which mayr extend into the Asocket ov the member A through the bore of a sleeve 11 on the member B, or through an aperture 12 of the member B1, as muy power shaft will preferably be independ- 'be evident that thev 5 will yicldably retain theloalls'(),1l and D in said ball-seats and relative rotai/l` be preferred. This The disentity mounted in bearings and i may be driven by a gear secured to another portion thereof. i

F indicates s power-driven member, here in the nature of a. geiir, forming a part of the transmission system for controlling the table movements of c milling machine or the like. r'his gear F is provided at 13 with n suitable clutch whereby it may be connected with the end of the sleeve ll extending 'from the member B.

lt is to be noted that various features and elements of this organization may be re-A placed in position and the parte may he variously arranged Without, however, departing from the r'nciplc oi this invention. Having r :led this invention, l claim ne" ond d to secure by Letters intent of the Unit@ States:m

l. A tr mission device of the nature disclosed combining e first series ot bells; s seo ont series of bells spaced away from scid .first series; o first member intervening betvveen said two series of balls and provided witlisoclets 'for individuzzllj,T receiving erich bell of scid series; second member heving a part provided with seats for individu-- ally receiving the bells of the one series, en oppositely located part having si series of seats adapted to receive the bells of the sec ond series; springs 'for resiliently position. ing seid bells to exert e thrust in opposite directions on the Darts of such second member to bilnnce said two members against relative lateral movement-l ineans 'for positively rotating one of said members, and ine-ans for derivingI motion from the other member.

2. A transmission device of the nature disclosed combining: :in annuler member pro 'iding :i series of apertures; balls located at the open ends ot each aperture; springs for urging seid bulls in opposite directions ont of seid apertures; e second member having :i serrated lince co-acting; with the balls at one end of apertures and an element rigid with .seid second member and provided with c serrated foce concting with the bells et the other end ot seid apertures;

3. transmission device of tbe nature disclosed. combining. a circumscribing member having' on annular side-wall provided with ai series of bell-scatsg an annular member concentrically Within. seid irst member: :i iirst series of bells yieldinglv carried by .said second member and co-acting with the' ball-seats of said irst member; :i second series of bells arranged in opposition to said first series and carried by said second member; a member nonrotzitnbly secured to said first member and having" o series of bollseats coecting with said second series orp bells; and means for adjusting said member laterally with relation to seid first memmechanism of the nature disclosed coini ining n motionirzinsniitting shaft; o lii'st andai second. sotb'zillsnrrsinged concentricziliv with said sho'lt; means for urging said bulls eport; menus lor restraining e revolution oi :uid bells about sold shaft: :l sleeve surrounding seid shaft und co:1cting with the one series ot' said bulls; und :i port non-rotatably sec'ilrefl to seid sleeve and cozicting; with tbe other series or' seid balls to bnlnnce the srreffcs thereof and to permit oit' n momentary ro rv movement between said and said shaft when it pre-'deter mined mn'fizinnun has been exceeded.

fi. il virlrlcble so.'letvcoupling oi' the netnre d l iininligf en unnular cirinivinsr n side-well pro- "crentinl series of brillyed to seid member :it a i woll :ind also having e sean annular member intervening' between said collar and said mill and :rv io; tivo series oi balls, springs for forcing' the bells the one series away from the balls of the other and into said bell-seats; rind means for adjusting the distene between seid coller :ind said well.

5 A yieldable safety-coupling of the nm ture disclosed combining fr first meuihe providing c plurality7 of seats; e corresponding number of friction-elements mounted in seid sects; e second member providing serrated portions arranged in opposition to said seats; and means 1tor urging saidlirictionelements in opposite directions to engage said portions with balanced stresses.

7. tinnsmission device of the nature dislosed combining :i first series of bulls; e second series of balls in coaxial relation with seid first series; :i first member positioning seid two series of balls and provided with seats for individually receiving the baile of said series; e second member having' portion arranged et one side of seid first member and provided with seats once ries of im ll- "for .ii'idividiuilljxr receiving the bulls of the one series; i port connected to said sof-ond member .nd lo ated et the opposite side of iiet member and also having :iis ries ot' adopte to receive the balls of the seeond series; springs 'tor resiliently position- 3j the bulls or the respective series in opp@- I'Lc direc" d members, :ind 'for defrom the other member.

li A trerisinission device of the nature disclosed combining an ennular member 'providing er plurality or' recesses arranged in two series; balls located et'thc open ends of cach recess; springs bearing on said balls ond exerting pressures in opposite directions with respect to seid member; sind a second insulin-ir having seats co-:lcting Withgsigid balls.

9. trensmissiondevice of the nature ns; ineens Jfor positively rotnt? disclosed combining a member having an annular side-wall provided with a series of ball-seats; anannular member coaxial with said first member; a first series of balls 5 yieldingly intervening between said members and co-acting with the ball-seats of said rst member; and a part non-rotatably secured to said first member and having a series of bal1-seats; a second series of balls l0 arranged between said part and said second member and co-acting with the ball-seats thereof.

10. A mechanism of the nature disclosed combining a motion-transmitting shaft; a

15 plurality of balls arranged conoentrically about said shaft; means Ior urging snm@ nf fin/imei said balls in opposite directions to others thereof, means for restraining a revolutionv BUBERT T. HAZELTON.

Nitnessesz Son EINsTEIN, H. T. WILLIAMS. 

